Proteasome subunit beta 7 (PSMB7) is one of the seven beta subunits of the 20S proteasome. The 20S proteasome has a barrel-like structure containing four stacked αββα rings. Each α or β ring is composed of seven different proteins. β1, β2 and β5 have peptidase activities that hydrolyze proteins. The corresponding catalytic subunits in immunoproteasomes are β1i, β2i and β5i subunits. The 20S proteasome can assemble with other protein complexes that activate the 20S proteasome to degrade proteins.